RANGE REPORT: DOUBLE TAP 10MM AMMO

Background.

On GlockTalk's 10Ring, Mike McNett is well-known to fans of the 10mm Auto. He's a reloading sage who, for many years, has generously shared his load data on this great cartridge. For those new to reloading, Mike is a friendly source of advice and more than willing to share his experiences. He now moderates GT's 10mm Reloading Forum, a place where 10mm shooters can exchange information about their pet loads.

This year, Mike finally started his own ammunition company, Double Tap Ammunition (DT), which specializes in several flavors of 10mm all having one thing in common: they're loaded very hot. While all the loads are within SAAMI pressures for the cartridge, DT's line-up is 10mm Auto at full-throttle. Indeed, DT safely exceeds the velocities and energy specs of Norma's original 10mm loads, which, historically, established the ballistic standards against which subsequent loads in this caliber are assessed. DT currently offers six different loads using bullet-weights of 135gns, 165gns, 180gns, 200gns and 220gns. (There are two 200gn loads, an XTP-HP and a FMJ-FP). Except for the 220gn FP and the 200gn XTP-HP, the other loads all produce muzzle energies above 700 foot-pounds - and even then the FP and XTP are knocking on the door at 680 fpe and 694 fpe, respectively. Moreover, the variety of bullet weights and types means that a particular load can be chosen for a specific application, although some can serve multiple roles. The 10mm/.40cal bullets that DT uses are among the best of currently available technology. Not just the Noslers or Golden Sabers, but the Hornady XTPs and FMJs too.

Ammo ordered.

For this Report, I ordered a quantity of DTs "untouchable" defensive ammo topped with Remington's 165gn and 180gn Golden Sabers (GS). (The 135gn Nosler HP load was not yet available). I was particularly interested in the accuracy and recoil characteristics of the 165gn GS load. This load, at 1425fps, is only 5 grains lighter than Norma's original 170gn 10mm HP at 1400fps, designed for the Bren Ten. Norma, at Dornaus & Dixon's request, later reduced the velocity to 1300fps. Nonetheless, in the mid-1980s, this 170gn load was touted as the prototype for police use on the street.

Golden Saber Hollow-Points.

In terms of bullet technology, Remington's GSHP is light years ahead of Norma's hard-edged, nonexpanding hollow-point. And that's of critical importance where the velocities involved meet or exceed original 10mm specs. Big Green describes its brass jacketed HPs as "high performance," and specifically markets them for "law enforcement, home security and personal defense applications." (Source: all quotes from Remington's 2003 catalog, p. 49). Remington asserts that its Golden Saber HP combines "four critical elements of handgun bullet performance: match-type accuracy, deep penetration, maximum expansion and virtually 100% weight retention." That's quite a statement, so I was looking forward to testing the GSs for accuracy and expansion when propelled at real 10mm speeds. The jacket is designed to "expand to a larger diameter than the lead core - over 1.6x caliber diameter," while the "minimal lead deformation retains energy for deeper penetration." The apparent purpose behind the brass jacket is to control mushrooming, thereby "releas[ing] energy over [a] longer distance." In other words: delayed expansion reduces deceleration of the HP in the body long enough to enhance the probability it will continue far enough to strike vital organs, as opposed to "explosive" mushrooming with little penetration. The GS bullet has angled "nose cuts" or grooves that go "completely through the jacket for better mushroom initiation over [the] widest range of practical velocities." Okay, what are "practical" velocities? Remington doesn't say, but in its 40S&W the 165gn GS is loaded to 1150fps and the 180gn GS to 1015fps. In contrast, DT's 165gn 10mm load is 275fps faster, while its 180gn load is 315fps faster.

Guns used.

From the 4.6" barrel of a Glock 20, DT specifies that velocity of the 180gn GSHP is 1330fps/707fpe, while the 165gn GSHP is 1425fps/744fpe. McNett has further stated that from a 5" barrel you should expect a gain of 25-30fps over the "boxflap" velocity. Thats good to know, because for this Report I used three common 10mm pistols, two of which have 5" barrels: a S&W 1006 and a customized Delta Elite. The third was my G20. The particulars on each of these pistols (with photos) are provided elsewhere on this site's "Collection" page. How DT's loads would perform from a 5" tube really interested me because that was the original length for which Norma's high-power 10mm was intended.

Test Procedure.

A total of 450rds were fired during range testing with three 10mm pistols. The 450rds breakdown as: 150rds fired through each gun (i.e., 75rds of each load through each gun). I tested for (1) reliability, (2) accuracy at distance and close in, (3) felt-recoil, and (4) penetration. The penetration tests are described separately below. Trust me when I say that with full-strength 10mm ammo, you dont have to fire that many rounds before you see how your gun performs. Be advised that if anything on it is weak, loose, out-of-spec, poorly installed or just plain defective, a hot 10mm load will bring that fact to your attention immediately. This includes sights, screws, pins, safeties, slide-stops, extractors and springs of all kinds, including those in your mags. A 10mm pistol that runs without a hitch firing Blazers' 200gn FMJ @ 1050fps can suddenly start hiccupping when the same bullet goes 200fps faster. Again, as the feet-per-second increase, anything "iffy" on your gun will be made known to you.

Reliability.

There were no malfunctions of any kind with the Smith 1006. I switched between 20lb & 22lb Wolff recoil springs with each DT load, and functioning was flawless. I'm sure the Wolff XP springs in the mags also helped, but this gun has yet to jam or fail to extract or eject with any type of hot 10mm load, including DT's.

With the Tibbets-customized Delta Elite, functioning was near perfect. The sole exception was a "stovepipe" jam that happened after firing about 50rds. At the time, I was using a 9-rd CMC mag with the 180gn load, and I'm still pretty sure it was a magazine problem, not an ammo problem. I had with me at the range some 8-rd Colt factory mags and other CMC mags. After noting the incident in my log, I put aside the suspect mag and continued shooting. No problems occurred with other mags, and there were no failures to feed, fire, extract or eject.

In the range bag with the G20, I brought along a "pre-ban" 15rd mag and a "post-ban" 10rd mag. I have several 10rd mags and use them for "practice" mags. When shooting DT loads from the 15rd mag, the gun ran smoothly. The G20 is stock, except for an ISMI captive 22lb spring and tritium night sights. With the 10rd mag, I had shot about 5 or 6 rds of the 165gn load when the slide-stop lever suddenly started engaging each time the gun fired. I removed the 10rd mag and loaded it full again, inserted it, released the slide and fired. Instant slide lockback. I released the slide again and it chambered the next round. I fired it, and the slide locked back again. I removed the 10rd mag, inserted the loaded 15rd mag, released the slide and fired. No problems whatsoever. The G20 shot and cycled all 15rds without a hitch until the slide locked back on the empty mag, like it should. That doesn't seem like an ammo issue, and I'm certain my finger wasn't hitting the slide-lever. It's probably not a weak spring under the lever either, but rather a weak spring in the 10rd mag. None of these mags ever gave me this problem before. I've ordered some Wolff XP mag springs, so we'll see if that cures it.

Accuracy.

The accuracy of DT's defensive ammo was impressive. The photos below show the typical accuracy from my guns. Testing took place at an outdoor range, and all shooting was done off-hand. No rests were used.

I tried two types of shooting with each load. First, close range or "combat distance" shooting was done from 5 yards. The idea was to assess controllability during rapid-fire through a full magazine. Starting from a two-hand "low ready" position, Weaver-type stance, I raised the pistol and fired as fast as I could get the front sight back on target - sort of a "front sight, press - front sight, press" technique. On some targets I tried double-tapping, but switching among three pistols gave mixed results. Ideally, you practice with one pistol until double-tapping becomes second nature with that gun and that load. While the G20 and the S&W 1006 were probably tied for best rapid-fire accuracy, there were really no "bad" targets. I avoided firing wildly for pure speed. It might be marginally faster, like "point shooting," but it doesn't get you very far. In the real world and in law enforcement, you're going to have to account for every shot fired, and you can't get the bullet back once it leaves the barrel. Still, the rapid-fire controllability of DT's defensive loads was manageable.

Distance shooting was done slow-fire, using a two-hand hold, with attention paid to sight picture, breath-control and correct trigger manipulation. The G20 and the S&W 1006 were shot from the 50-foot line. Because the Delta has a hand-fitted Bar-Sto barrel, I shot it from 60-feet (20 yards). Generally speaking, groups of 2"-2.5" were the norm for the G20 and S&W 1006. The Delta turned in several 1.5" and a few 2" groups, excluding flyers. As a final test, I took the Delta back to 25 yards, where I fired 18-shots of the165gn GSs at a 5" Shoot-N-C bullseye. (Flyers were my fault and are circled in the photos below).

While the shooter is always part of the equation, the accuracy of DT's Golden Saber loads was excellent. This is quality ammunition and there is definitely shot-to-shot consistency.

Felt recoil.

Maybe it's the special powder McNett uses, but given the claimed velocities, recoil wasn't bad at all. That said, each gun exhibited different recoil characteristics. The recoil of DT's loads really only matters where speed is an issue, and even then frequent practice increases your ability to handle it. Still, there's the platform to consider. Of the three guns used, recoil in the S&W 1006 was a nonissue. This gun is an all-steel tank, and between its recoil-dampening weight and the Hogue rubber grips, it was sheer fun shooting both loads.

About the same can be said for the G20. With full-strength loads, you begin to understand how the Glock's heavy steel slide, flexing polymer frame, wide grip and low bore-grip axis all work together to absorb and spread recoil.

The Delta normally uses a 22lb Wolff variable recoil spring, but for this test I installed a 24lb spring. Recoil with the 180gn load, while "felt" more than in the others, wasn't bad at all, being more of a stout straight-back push. Though all steel too, the Delta is lighter than the 1006 and has a narrower grip. But Vic Tibbets' work on the ergonomics, like the front-strap checkering and high-sweep BT grip safety, allowed for greater control with less perceived "snap" than on a stock gun.

Penetration. These tests were certainly not definitive, and as time permits I'd like to do more with both loads.

Test #1: Phone books & denim. For this test I used my Delta with the 165gn GS. Two medium-sized phonebooks were soaked in water overnight. They were duct-taped around the edges only enough to keep them together. Water-swollen, they measured just under 8.5" through the center. At the range, I placed the phonebooks inside some little-worn denim shorts, which added about half an inch to the total thickness, and then set the whole thing up on a stand. For point of aim, I marked a spot on the denim where the bullet would have to traverse the full thickness of the books, and then went back 30 feet (10 yards). I fired one shot, which hit about where I'd marked. The books moved a bit, but not much and there was a small entrance hole in the denim. Cutting off the duct tape, I found a lot of shreaded paper with a progressively larger hole through it, leading out the other side. At first I couldn't find an exit hole in the denim. Then I saw there was none, because the GS had come to rest neatly in the left front pocket of the shorts. The recovered slug showed full, textbook expansion. The exposed lead was flattened, and the petals were peeled all the way back and around the off-side. Retained weight was 166 grains, which obviously included denim and paper debris trapped in the petals. (See photos below). According to my calipers, the diameter of the flattened lead is 0.659. This is consistent with Remington's claim that expansion should be "1.6x caliber diameter" (i.e., 1.6 x .400 = .640).

Test #2: Beef & denim. For this test, my Smith 1006 and the 180gn GS were used. I purchased several types of meat: a 1" thick t-bone steak and several slices of boneless beef of varying thicknesses and grizzle-content. I put the t-bone steak in the middle of the other beef slabs, so they more or less formed one pile or "brick" of meat. I then wrapped this "brick" in a single layer of thin plastic wrap. I placed the wrapped meat, now just over 5.5" thick, inside a large ziplock bag. I filled the bag about 2/3rds of the way with water, let the air out and closed it up. The total thickness of the bag with the beef & water was now about 7.5"-8." The idea here was to approximate not only human muscle and sinew, but also the layers of membrane and fluids that make up vital organs and surrounding areas. I then put the bag inside some old denim jeans, as before, to add the element of an intermediate barrier of clothing. I went back to 30 feet and fired a single shot, the point of aim being the center of the thickest part of the denim/meat/water unit. The 180gn GS penetrated directly through the denim into the meat, causing the water to drain out and soak the jeans. The bullet broke off a piece of steak bone, and fragments of bone and denim material were carried into the "wound path." However, the bullet exited the opposite side and could not be recovered. (See photos below). Thus, the expansion issue is inconclusive. A closer look revealed a large hole through the rear of the "brick" where the meat was violently disrupted - damage with a capital "D." The GS must have expanded some before exiting, but just how much is unknown. I found no evidence of bullet disintegration.

Conclusions.

Mike McNett has done well. Double Tap's 10mm loads were quite accurate and their power level is reasonably controllable for those who are serious about using the 10mm Auto. While a few companies load this cartridge at or near its original specs, Double Tap offers what is arguably the best and widest line-up of "high-power" 10mm available in the United States today.

I also think McNett hit a home run in choosing the Golden Sabers for these velocities. Against denim and wet phone books the 165gn GS did what it was designed to do. At this energy level, it is probably the perfect "all seasons" defensive load. For those living in hot-weather states, thin-walled apartments or dense urban centers, you might try DT's new 135gn Nosler HP load. In rural areas or in cold weather regions, where an assailant would likely wear bulky winter gear, thick leather or layered clothing beneath a heavy outer coat, and anywhere else penetration is a priority, the 180gn GS is probably a better choice. Among premium self-defense ammo in 10mm, this load defines "heavy & fast."

Hopefully, DT will add to its 10mm line-up an economical "practice" load that approximates the velocities of its GSs.

A final word to the wise: unlike other calibers out there, the 10mm Auto at full-power can be a harsh mistress for the "once-a-month-warrior." Hand-eye coordination and muscle memory develop over time. They are perishable and will fade quickly without repeated range sessions. If you intend to carry such loads for duty or CCW, then you need to practice regularly to achieve - and maintain - proficiency and good shooting technique.